A dielectric boundary surface estimation device is used for measuring a state in a dielectric utilizing a property of passing through an inside of the dielectric which is a property of a radio wave as a wave, and contributes to cancer detection and diagnosis of material deterioration of a construction.
In the cavity thickness investigating method disclosed in following Patent Literature 1, scattering from a dielectric boundary point is observed with S transform processing. In this method, not a boundary surface but only a boundary point of a dielectric is measured. As for measurement of the shape of a dielectric, an ellipsoid is simply applied on a basis of visual observation irrespective of S transform and no special plan is devised.